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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of information and communication convergence engineering
Journal Basic Information
Journal DOI :
The Korean Institute of Information and Commucation Engineering
Editor in Chief :
Volume & Issues
Volume 10, Issue 4 - Dec 2012
Volume 10, Issue 3 - Sep 2012
Volume 10, Issue 2 - Jun 2012
Volume 10, Issue 1 - Mar 2012
Selecting the target year
Minimizing the Average Distance of Separated Points on the Plane in the L
Kim, Jae-Hoon ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 1~4
DOI : 10.6109/jicce.2012.10.1.001
Given separated points divided by a line, called a wall, in a plane, we aim to make a gate in the wall to connect the separated points to each other. In this setting, the problem is to find a location for the gate that minimizes the average distance between the points. The problem is a variant of the well-known facility location problem, which is extensively studied in the fields of operations research, location theory, theoretical computer science, and so on. In this paper, we consider the
-distance of the points in the plane. The points are projected onto the wall and so the problem is transformed to a proximity problem of points on a line. Then it is shown that the transformed problem is related to the weighted median problem of points on the line. Therefore, we obtain an O(n log n)-time algorithm to solve our problem.
Current State of and Cutoff Schemes for Academic Misconducts in the Cyber Classes
Woo, Jong-Jung ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 5~10
DOI : 10.6109/jicce.2012.10.1.005
The cyber class has many advantages because it removes the limitations of sharing the same time and space of a class in a classroom. However, most instructors still hesitate to use it because it is more vulnerable to academic misconduct than a faceto- face class. To overcome this problem, we identified suspected cheaters out of a group of test-takers through several objective data, and verified whether or not the suspects were actually cheaters. By investigating the status of academic cheating, we also implement our assessment system with Skinner’s reinforcement theory in order to eliminate or reduce cyber misconducts.
Discovery of and Recovery from Failure in a Costal Marine USN Service
Ceong, Hee-Taek ; Kim, Hae-Jin ; Park, Jeong-Seon ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 11~20
DOI : 10.6109/jicce.2012.10.1.011
In a marine ubiquitous sensor network (USN) system using expensive sensors in the harsh ocean environment, it is very important to discover failures and devise recovery techniques to deal with such failures. Therefore, in order to perform failure modeling, this study analyzes the USN-based real-time water quality monitoring service of the Gaduri Aqua Farms at Songdo Island of Yeosu, South Korea and devises methods of discovery and recovery of failure by classifying the types of failure into system element failure, communication failure, and data failure. In particular, to solve problems from the perspective of data, this study defines data integrity and data consistency for use in identifying data failure. This study, by identifying the exact type of failure through analysis of the cause of failure, proposes criteria for performing relevant recovery. In addition, the experiments have been made to suggest the duration as to how long the data should be stored in the gateway when such a data failure occurs.
Adjusting Transmission Power for Real-Time Communications in Wireless Sensor Networks
Kim, Ki-Il ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 21~26
DOI : 10.6109/jicce.2012.10.1.021
As the new requirements for wireless sensor networks are emerging, real-time communications is becoming a major research challenge because resource-constrained sensor nodes are not powerful enough to accommodate the complexity of the protocol. In addition, an efficient energy management scheme has naturally been a concern in wireless sensor networks for a long time. However, the existing schemes are limited to meeting one of these two requirements. To address the two factors together, we propose real-time communications with two approaches, a protocol for satisfied conditions and one for unsatisfied. Under the satisfied requirement, existing real-time protocol is employed. On the other hand, for the unsatisfied requirement, the newly developed scheme replaces the existing scheme by adjusting the transmission range of some surplus nodes. By expanding the transmission range, the end-to-end delay is shortened because the number of intermediate nodes decreases. These nodes conserve their energy for real-time communications by avoiding other activities such as sensing, forwarding, and computing. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic environments.
Analysis of Similarity of Twitter Topic Categories among Regions
Yun, Hong-Won ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 27~32
DOI : 10.6109/jicce.2012.10.1.027
Twitter can spread and share all kinds of information such as facts, opinions, and ideas in real time. In this paper, we empirically compare and analyze the topic categories in Twitter with all top 100 users in each of geographic region. We mainly consider the relationships among regions and selected four regions: Global, Seoul, Tokyo, and Beijing. Each of the top 100 users in Twitter is classified into a specific category and then statistical analysis is conducted. Among eight topic categories, the "Arts" category is the largest and the second is "Life". The correlation between global and Seoul groups has the lowest value among the six pairs of relationships between regional groups, and this difference is statistically significant. We find that the Seoul, Tokyo, and Beijing regional Twitter groups, all in East Asia, have high topical similarity. Based on the correlation analysis, Seoul and Tokyo saliently show a sticky trend. The correlation coefficient presents very a strong positive correlation between Seoul and Tokyo. The correlation between the global group and the East Asian groups is relatively lower than that among the East Asian groups.
On the Accuracy of RFID Tag Estimation Functions
Park, Young-Jae ; Kim, Young-Beom ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 33~39
DOI : 10.6109/jicce.2012.10.1.033
In this paper, we compare the accuracy of most representative radio frequency identification (RFID) tag estimation functions in the context of minimizing RFID tag identification delay. Before the comparisons, we first evaluate the accuracy of Schoute`s estimation function, which has been widely adopted in many RFID tag identification processes, and show that its accuracy actually depends on the number of tags to be identified and frame size L used for dynamic frame slotted Aloha cycles. Through computer simulations, we show how the accuracy of estimation functions is related to the actual tag read performance in terms of identification delay.
Gene Algorithm of Crowd System of Data Mining
Park, Jong-Min ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 40~44
DOI : 10.6109/jicce.2012.10.1.040
Data mining, which is attracting public attention, is a process of drawing out knowledge from a large mass of data. The key technique in data mining is the ability to maximize the similarity in a group and minimize the similarity between groups. Since grouping in data mining deals with a large mass of data, it lessens the amount of time spent with the source data, and grouping techniques that shrink the quantity of the data form to which the algorithm is subjected are actively used. The current grouping algorithm is highly sensitive to static and reacts to local minima. The number of groups has to be stated depending on the initialization value. In this paper we propose a gene algorithm that automatically decides on the number of grouping algorithms. We will try to find the optimal group of the fittest function, and finally apply it to a data mining problem that deals with a large mass of data.
A Study on Wavelet-based Image Denoising Using a Modified Adaptive Thresholding Method
Yinyu, Gao ; Kim, Nam-Ho ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 45~52
DOI : 10.6109/jicce.2012.10.1.045
Thedenoising of a natural image corrupted by Gaussian noise is a long established problem in signal or image processing. Today the research is focus on the wavelet domain, especially using the wavelet threshold method. In this paper, a waveletbased image denoising modified adaptive thresholding method is proposed. The proposed method computes thethreshold adaptively based on the scale level and adaptively estimates wavelet coefficients by using a modified thresholding function that considers the dependency between the parent coefficient and child coefficient and the soft thresholding function at different scales. Experimental results show that the proposed method provides high peak signal-to-noise ratio results and preserves the detailed information of the original image well, resulting in a superior quality image.
Attribute-based Proxy Re-encryption with a Constant Number of Pairing Operations
Seo, Hwa-Jeong ; Kim, Ho-Won ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 53~60
DOI : 10.6109/jicce.2012.10.1.053
Attribute-based encryption (ABE) is an encryption scheme in which the user is able to decrypt a ciphertext with associated attributes. However, the scheme does not offer the capability of decryption to others when the user is offline. For this reason, the attribute-based proxy re-encryption (ABPRE) scheme was proposed, which combines traditional proxy re-encryption with ABE, so a user is able to empower designated users to decrypt the re-encrypted ciphertext with the associated attributes of designated users. However, previous ABPRE schemes demands a number of pairing operations that imply huge computational overhead. To reduce the number of pairing operations, we reduce the pairing operations with exponent operations. This paper provides a novel approach to an ABPRE scheme with constant pairing operation latency.
A Strategy for Adopting Server Virtualization in the Public Sector: NIPA Computer Center
Song, Jong-Cheol ; Ryu, Jee-Woong ; Moon, Byung-Joo ; Jung, Hoe-Kyung ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 61~65
DOI : 10.6109/jicce.2012.10.1.061
Many public organizations have been adopting and operating various servers. These servers run on Windows, Unix, and Linux operating systems that generally use less than 10% of their capacity. For migrating a public organization to cloud computing, we must first virtualize the server environment. This article proposes a strategy for server virtualization that the National IT Industry Promotion Agency (NIPA) has done and describes the effects of a public organization migrating to cloud computing. The NIPA Computer Center planned an effective virtualization migration on various servers. This project of virtualization migration was conducted with the existing policy of separate x86 servers and Unix servers. There are three popular approaches to server virtualization: a virtual machine model, a paravirtual machine model, and virtualization at the operating system layer. We selected a VMware solution that uses the virtual machine model. We selected servers for virtualization in the following manner. Servers were chosen that had the highest rate of service usage and CPU usage and had been operating for five years or more. However, we excluded servers that require 80% or greater rates of CPU usage. After adopting the server virtualization technique, we consolidated 32 servers into 3 servers. Virtualization is a technology that can provide benefits in these areas: server consolidation and optimization, infrastructure cost reduction and improved operational flexibility, and implementation of a dual computing environment.
A Study on the Methods for Solving the Theodorsen Equation for Numerical Conformal Mapping
Song, Eun-Jee ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 66~70
DOI : 10.6109/jicce.2012.10.1.066
Conformal mapping has been a familiar tool of science and engineering for generations. Determination of a conformal map from the unit disk onto the Jordan region is reduced to solving the Theodorsen equation, which is an integral equation for boundary correspondence functions. There are many methods for solving the Theodorsen equation. It is the goal of numerical conformal mapping to find methods that are at once fast, accurate, and reliable. In this paper, we analyze Niethammer’s solution based on successive over-relaxation (SOR) iteration and Wegmann’s solution based on Newton iteration, and compare them to determine which one is more effective. Through several numerical experiments with these two methods, we can see that Niethammer’s method is more effective than Wegmann’s when the degree of the problem is low and Wegmann’s method is more effective than Niethammer’s when the degree of the problem is high.
The Impact of Information System Quality and Media Quality on the Intention to Use IPTV
Lee, Dong-Man ; Chae, Young-Su ; Lee, Young-Ki ; Choi, Moon-Jong ; Jang, Sung-Hee ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 71~77
DOI : 10.6109/jicce.2012.10.1.071
This study examines the factors influencing internet protocol television (IPTV) usage intention. Using Davis`s technology acceptance model (TAM) and DeLone and McLean`s model of information system success, this study investigates the effects of information system quality (information quality, system quality, and service quality) and media quality on IPTV use in terms of perceived usefulness, perceived ease of use, and usage intention. We examined the proposed model by employing structural equation modeling and survey data from 222 IPTV users. The results indicate that information quality, service quality, and media quality had significant effects on perceived usefulness and that information quality and media quality had significant effects on perceived ease of use. However, system quality had no effect on perceived usefulness or perceived ease of use. In addition, perceived ease of use influenced perceived usefulness, and perceived usefulness and perceived ease of use influenced IPTV usage intention. Further, the stability and reliability of IPTV services encouraged IPTV use, and successful IPTV services showed high media quality.
Performance Improvement and Power Consumption Reduction of an Embedded RISC Core
Jung, Hong-Kyun ; Jin, Xianzhe ; Ryoo, Kwang-Ki ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 78~84
DOI : 10.6109/jicce.2012.10.1.078
This paper presents a branch prediction algorithm and a 4-way set-associative cache for performance improvement of an embedded RISC core and a clock-gating algorithm with observability don’t care (ODC) operation to reduce the power consumption of the core. The branch prediction algorithm has a structure using a branch target buffer (BTB) and 4-way set associative cache that has a lower miss rate than a direct-mapped cache. Pseudo-least recently used (LRU) policy is used for reducing the number of LRU bits. The clock-gating algorithm reduces dynamic power consumption. As a result of estimation of the performance and the dynamic power, the performance of the OpenRISC core applied to the proposed architecture is improved about 29% and the dynamic power of the core with the Chartered 0.18
technology library is reduced by 16%.
A 1.8 V 40-MS/sec 10-bit 0.18-㎛ CMOS Pipelined ADC using a Bootstrapped Switch with Constant Resistance
Eo, Ji-Hun ; Kim, Sang-Hun ; Kim, Mun-Gyu ; Jang, Young-Chan ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 85~90
DOI : 10.6109/jicce.2012.10.1.085
A 40-MS/sec 10-bit pipelined analog to digital converter (ADC) with a 1.2 Vpp differential input signal is proposed. The implemented pipelined ADC consists of eight stages of 1.5 bit/stage, one stage of 2 bit/stage, a digital error correction block, band-gap reference circuit & reference driver, and clock generator. The 1.5 bit/stage consists of a sub-ADC, digital to analog (DAC), and gain stage, and the 2.0 bit/stage consists of only a 2-bit sub-ADC. A bootstrapped switch with a constant resistance is proposed to improve the linearity of the input switch. It reduces the maximum VGS variation of the conventional bootstrapped switch by 67%. The proposed bootstrapped switch is used in the first 1.5 bit/stage instead of a sample-hold amplifier (SHA). This results in the reduction of the hardware and power consumption. It also increases the input bandwidth and dynamic performance. A reference voltage for the ADC is driven by using an on-chip reference driver without an external reference. A digital error correction with a redundancy is also used to compensate for analog noise such as an input offset voltage of a comparator and a gain error of a gain stage. The proposed pipelined ADC is implemented by using a 0.18-
1- poly 5-metal CMOS process with a 1.8 V supply. The total area including a power decoupling capacitor and the power consumption are 0.95
and 51.5 mW, respectively. The signal-to-noise and distortion ratio (SNDR) is 56.15 dB at the Nyquist frequency, resulting in an effective number of bits (ENOB) of 9.03 bits.
Design of Filter to Reject Motion Artifacts of PPG Signal by Using Two Photosensors
Lee, Ju-Won ; Nam, Jae-Hyun ;
Journal of information and communication convergence engineering, volume 10, issue 1, 2012, Pages 91~95
DOI : 10.6109/jicce.2012.10.1.091
The photoplethysmography (PPG) signal measured from a mobile healthcare device contains various motion artifacts occurring from a patient’s movements. Recently, to reject the motion artifacts, the method of using an acceleration sensor was suggested, but such sensors are very expensive. Therefore, this study deals with a novel sensor device to replace the acceleration sensor, and evaluated the performance of the proposed sensor experimentally. In the results of the experiments, it is shown that the proposed sensor device can reconstruct the PPG signal despite the occurrence of motion artifacts, and also that the variation rate in heart rate analysis was 1.22%. According to the experimental results, the proposed method can be applied to design a low-cost device.